1. Field of the Invention
The present invention relates to an apparatus for heat-treating a V-type cylinder block by induction heating, wherein the cylinder block is of a diesel engine and the like used under heavy loads and the apparatus is employed to produce, for example, a predetermined mottled pattern of a plurality of quenched layer portions arranged in an inner peripheral surface of each of a plurality of cylinder bores of such cylinder block.
2. Description of the Related Art
For example, in an inner peripheral surface of a cylinder bore of a diesel engine and the like used under a heavy load, there is formed a mottled pattern of individually quenched layer portions through a conventional inner surface quenching method. In this connection, the applicant of the present application has already proposed an induction heating coil and an induction quenching method in Japanese Patent Laid-Open Nos. Hei 7-161461 and Hei 7-272845.
However, such conventional quenching method with induction heating is disadvantageous in that: when a center of the cylinder bore deviates from that of the induction heating coil to fail to keep constant a clearance between an inner peripheral surface of the cylinder bore and an outer peripheral surface of the induction heating coil, the induction heating coil fails to evenly heat the inner peripheral portion of the cylinder bore, which makes it impossible to produce a constant pattern of quenched portions of the cylinder bore, so that the quenched portions of the cylinder bore differs from each other also in quenching depth. Consequently, in order to produce the constant pattern of quenched portions of the cylinder bore, it is necessary for the induction heating coil to position its center within a radius of several tens of microns from the center of the cylinder bore when the quenching of the cylinder bore is carried out. However, such positioning operation of the induction heating coil is very cumbersome when an engine""s cylinder block is provided with a plurality of the cylinder bores to be quenched. Due to such cumbersomeness, the positioning operation of such a single induction heating coil described above is not suitable for a quenching method for mass production.
Consequently, in order to solve the above problem, the inventors of the present invention have disclosed their previous invention entitled xe2x80x9cPRECISION QUENCHING APPARATUS AND METHOD WITH INDUCTION HEATINGxe2x80x9d (for heat treatment of an in-line type cylinder block) in Japanese Patent Laid-Open No. Hei 8-225846, which invention was also filed in U.S.A. and already matured into U.S. Pat. No. 6,024,913 on Feb. 15, 2000. This U.S. Patent is incorporated herein by reference.
Incidentally, the precision quenching apparatus for heat treatment of the in-line type cylinder block of the above previous invention (hereinafter referred to as the previous apparatus) employs a single induction heating coil. In heat treating a workpiece (i.e., the in-line type cylinder block), the workpiece travels while having an inner surface of each of its cylinder bores subjected to heat treatment performed by such a single induction heating coil. Due to this, in the case where another type of workpiece such as a V-type cylinder block provided with a first and a second row of cylinder bores is heat-treated using the previous apparatus, it is necessary for the previous apparatus to perform the heat-treating process twice. In other words, the first row and the second row of the cylinder bores of the workpiece (i.e., V-type cylinder block) are subjected to a first and a second heat-treating process, respectively, which makes the previous apparatus complicated in construction and worse in working efficiency due to the necessity of a longer processing time. The above is a problem inherent in the previous apparatus.
Consequently, it is an object of the present invention to provide an apparatus for efficiently heat-treating a V-type cylinder block by induction heating necessary to perform a quenching and a tempering operation, wherein the cylinder block is provided with a first and a second row of cylinder bores, both of which rows are simultaneously heat-treated using a plurality of induction heating coils in a condition in which the induction heating coils travel while the cylinder block is held stationarily.
In accordance with a first aspect of the present invention, the above object of the present invention is accomplished by providing:
A heat-treatment apparatus for quenching a V-type cylinder block (W) by induction heating, comprising:
a work table (11) on which the cylinder block (W) is fixedly mounted in a reference position thereon, wherein the work table (11) is fixedly mounted on a base frame (10);
a plurality of induction heating coils (23) each for heating an inner surface of each of a plurality of cylinder bores (wn) of the cylinder block (W); and
a transfer table assembly (13, 18, 21) for supporting the induction heating coils (23) in a manner such that each of the heating coils (23) is movable in a reciprocating manner in parallel with a longitudinal axis of each of the cylinder bores (Wn) to enter and exit from each of the cylinder bores (Wn) and also movable in a direction in parallel with each of rows of the cylinder bores (Wn) in a reciprocating manner; wherein the transfer table assembly (13, 18, 21) is movably mounted on each of opposite sides of the base frame (10) to sandwich the work table (11) therebetween.
In accordance with a second aspect of the present invention, the above object of the present invention is accomplished by providing:
The heat-treatment apparatus for quenching the V-type cylinder block (W) by induction heating as set forth in the first aspect of the present invention, wherein the transfer table assembly (13, 18, 21) is constructed of:
an X table (13) which travels in a direction X in parallel with the rows of the cylinder bores (Wn) along an upper surface of the base frame (10);
a Y table (18) movably mounted on the X table (13), wherein the Y table (18) travels in a direction Y perpendicular to the direction X along the upper surface of the base frame (10); and
a Z table (21) movably mounted on the Y table (18), wherein the Z table (21) supports the induction heating coils (23) to travel in a direction (Z) along an upper inclined surface of the Y table (18), wherein the upper inclined surface of the Y table (18) extends in parallel with the longitudinal axis of each of the cylinder bores (Wn).
In accordance with a third aspect of the present invention, the above object of the present invention is accomplished by providing:
The heat-treatment apparatus for quenching the V-type cylinder block (W) by induction heating as set forth in the second aspect of the present invention, wherein:
the work table (11) is provided with a reference member (36) for determining a position of each of the cylinder bores (Wn) of the cylinder block (W) in a coordinate system;
the Y table (18) is provided with a position determining means (31) for determining the coordinates of each of the reference member (36) and the cylinder bores (Wn) of the cylinder block (W); and
a control means (100) is provided to control in position the transfer table assembly (13, 18, 21) on the basis of the coordinates of each of the reference member (36) and said cylinder bores (Wn) in a manner such that said induction heating coils (23) are capable of entering and exiting from said cylinder bores (Wn) of said cylinder block (W).
In accordance with a fourth aspect of the present invention, the above object of the present invention is accomplished by providing:
The heat-treatment apparatus for quenching the V-type cylinder block (W) by induction heating as set forth in the third aspect of the present invention, wherein the position determining means (31) is movably mounted on the Y table (18) in a manner such that the position determining means (31) is movable in parallel with a longitudinal axis of each of the cylinder bores (Wn) of the cylinder block (W) along the upper inclined surface of the Y table (18).
In accordance with a fifth aspect of the present invention, the above object of the present invention is accomplished by providing:
The heat-treatment apparatus for quenching the V-type cylinder block (W) by induction heating as set forth in the second or the fourth aspect of the present invention, wherein:
each of the induction heating coils (23) is supported on the Z table (21) so as to be rotatable in a direction (xcex8); and
the control means (100) is provided with a control portion (101) for controlling each of the induction heating coils (23) in its rotational motion.
In accordance with a sixth aspect of the present invention, the above object of the present invention is accomplished by providing:
The heat-treatment apparatus for quenching the V-type cylinder block (W) by induction heating as set forth in any one of the second, fourth and the fifth aspect of the present invention, wherein:
the reference member (36) assumes substantially the same V-type shape as that of the cylinder block (W) in cross section, and is provided with a pair of gauge rings (37) each of which is identical in inner diameter with each of the cylinder bores (Wn) of the cylinder block (W); and
the position determining means (31) is provided with an inner-diameter measuring head portion (32), and constructed of an inner-diameter measuring instrument for determining a clearance between an inner diameter of the gauge ring (37) and an outer diameter of the inner-diameter measuring head portion (32) of the position determining means (31).
In accordance with a seventh aspect of the present invention, the above object of the present invention is accomplished by providing:
The heat-treatment apparatus for quenching the V-type cylinder block (W) by induction heating as set forth in any one of the third, fourth, fifth and the sixth aspect of the present invention, wherein:
a cooling tank (41) is fixedly mounted on an upper surface of the work table (11) and filled with a cooling liquid in which the cylinder block (W) is immersed, heated by induction heating and quenched by the cooling liquid upon de-energizing of said induction heating coils (23).
In accordance with an eighth aspect of the present invention, the above object of the present invention is accomplished by providing:
The heat-treatment apparatus for quenching the V-type cylinder block (W) by induction heating as set forth in any one of the third to the seventh aspect of the present invention, wherein: the cylinder block (W) has the cylinder bores spaced apart from and parallel to each other at predetermined intervals (A); and, a control means (100) for realizing quenching operation of the cylinder block (W) is provided in the apparatus, the quenching operation comprising the steps of:
1) set a master block (M) at a reference position on the work table (11) in a manner such that the master block (M) has each of rows of its cylinder bores (Mn) aligned with the direction X, wherein the master block (M) is substantially identical in shape and dimensions with the cylinder block (W);
2) move the X table (13) and the Y table (18) to a position in which the position determining means (31) mounted on the Y table (18) coincides in center with the reference member (36) mounted on the work table (11), wherein coordinates (Xo, Yo) of the position are measured;
3) move the X table (13) and the Y table (18) to a first position in which the position determining means (31) coincides in center with a first one (M1) of the cylinder bores (Mn) of the master block (M), wherein coordinates (X1, Y1) of the first position are measured;
4) calculate coordinates (X1+(nxe2x88x921)A, Y1) of a new position of the X table (13) and the Y table (18) on the basis of the coordinates (X1, Y1) of the first position, in which new position the position determining means (31) coincides in center with an n""th one (Mn) of the cylinder bores of the master block (M), wherein the cylinder bores of the master block (M) are spaced apart from and parallel to each other at predetermined intervals (A);
5) move the X table (13) and the Y table (18) to a xe2x80x9cpxe2x80x9d position in which the first cylinder bore (M1) coincides in center with the induction heating coil (23), wherein coordinates (Xp, Yp) of the xe2x80x9cpxe2x80x9d position are measured;
6) store all the coordinates defined above in the control means (100);
7) replace the master block (M) with the cylinder block (W) in the reference position on the work table (11);
8) move the X table (13) and the Y table (18) to a position in which each of the cylinder bores (Wn) of the cylinder block (w) coincides in center with each of the induction heating coils (23), wherein coordinates ((X1+(nxe2x88x921)A+an), (Y1+bn)) of the position are measured;
9) move the X table (13) and the Y table (18) to a position of coordinates ((Xp+(nxe2x88x921)Axe2x88x92an), (Ypxe2x88x92bn)) in which an inner surface of an n""th one of the cylinder bores (Wn) of the cylinder block (W) is subsequently subjected to an induction heating and a quenching operation, wherein the xe2x80x9canxe2x80x9d and the xe2x80x9cbnxe2x80x9d are deviation values deviated from set values;
10) quench both the rows of cylinder bores (wn) of the V-type cylinder block (W) in the same manner as that described above.
In accordance with a ninth aspect of the present invention, the above object of the present invention is accomplished by providing:
A heat-treatment apparatus for tempering a V-type cylinder block (W) by induction heating, comprising:
a work table (51) on which the cylinder block (W) is fixedly mounted in a reference position thereon, wherein the work table (51) is fixedly mounted on a base frame (50);
a plurality of induction heating coils (59) for heating an inner surface of each of a plurality of cylinder bores (wn) of the cylinder block (W); and
a transfer table assembly (53, 55) for supporting the heating coils (59) in a manner such that each of the heating coils (59) is movable in a reciprocating manner in parallel with a longitudinal axis of each of the cylinder bores (Wn) to enter and exit from each of the cylinder bores (Wn); wherein the transfer table assembly (53, 55) is movably mounted on each of opposite sides of the base frame (50) to sandwich the work table (51) therebetween.